Researchers have recognized that a family of enzymes known as protein kinase C enzymes is associated with a large number of cancers. This family includes at least eleven isoenzymes. A particular member of this family is identified as the protein kinase C alpha enzyme, abbreviated: PKC .alpha..
Researches have reported increases in PKC .alpha. activity in human breast tumors (NG et al., Science. 283:2085-2089) and significant increases in PKC .alpha. expression in prostate cancers (Cornford et al., Am. J. Pathol. 154: 137-144). Researchers have reported that PKC .alpha. is required for the metastasis of human melanoma (Dennis et al., Cancer Lett. 128:65-70) and that PKC .alpha. is related to the progression of brain tumors (Shen et al., Mol. Pharmacol. 55:396-402). There is general agreement among many cancer researchers that some of the most dangerous cancers can be treated with chemotheraputic agents or specially designed oligonuclotides targeted to PKC .alpha..
Recently, Muller et al were granted a patent, U.S. Pat. No. 5,744,460, which discloses a cancer treatment utilizing an antisense oligonuclotide targeted to PKC .alpha. combined with a chemotherapeutic agent. U.S. Pat. Nos. 5,882,927 and 5,885,970 issued to Bennett et al also disclose antisense oligonuclotides targeted to PKC. Several patents that disclose PKC .alpha. inhibitors for treating cancers have been issued to Heath, Jr., et al. These include U.S. Pat. No. 5,843,935. U.S. Pat. No. 5,723,456 is another example of a cancer treatment in which a PKC directed emzyme is proposed as a method to treat cancer. U.S. Pat. No. 5,821,072 granted to Schwartz, et al proposes the use of certain chemotherapeutic agents to attempt to reduce PKC activity. The disclosures of the above listed patents are incorporated herein by reference.
A chemical known as Go6976, available from Calbiochem Corp. and Alexis Corp. (both with offices in San Diego, Calif.), is known to be an inhibitor of PKC .alpha.. Go6976 is designated as C24H18N40 and a diagram of the molecule is presented in FIG. 1. Applicant et al reported in Molecular Cellular Biology, 17:3418-3428 based on a variety of experiments that Go6976 prevented TPA-induced downregulation of the of PKC .alpha. and is a more specific inhibitor for PKC .alpha..
What is needed is a better treatment for cancer.